The present disclosure relates to mechanically attached connections such as fittings, joints, couplings, unions and so on that are used in fluid systems or fluid circuits to contain fluid flow and fluid pressure. Such mechanically attached connections may be used with but are not limited to conduit fittings for tube, pipe or any other type of conduit, and that connect a conduit end to either another conduit end or to another portion, element or component of a fluid system. For simplicity and clarity, the term ‘fitting’ as used herein is intended to be all inclusive of other terms, for example coupling, connection, union, joint and so on, that could alternatively be used to refer to a mechanically attached connection. Such mechanically attached connections are characterized by a fluid tight seal and mechanical strength to hold the connection together including sufficient grip of the conduit under vibration, stress and pressure. Fluids may include gas, liquid, slurries and any variation or combination thereof.
Fluid systems and circuits typically use mechanically attached connections to interconnect conduit ends to each other and to flow devices which may control flow, contain flow, regulate flow, measure one or more characteristics of the fluid or fluid flow, or otherwise influence the fluid within the fluid system. Fluid systems are found everywhere, from the simplest residential plumbing system, to the most complex fluid systems for the petrochemical, semiconductor, biopharmaceutical, medical, food, commercial, residential, manufacturing, analytical instrumentation and transportation industries to name just a few examples. Complex systems may include thousands of fittings, either fittings being installed as a new installation or as part of repair, maintenance or retrofit operations, or fittings that were previously installed.
The term ‘mechanically attached connection’ as used herein means any connection for or in a fluid system that involves at least one connection that is held in place by mechanically applied force, stress, pressure, torque, or the like, such as, for example, a threaded connection, a clamped connection, a bolted or screwed connection and so on. This is distinguished from a metallurgical or chemical connection most commonly practiced as welding, brazing, soldering, adhesive and so forth. A mechanically attached connection may include a combination of mechanical and metallurgical connections, and often does, and such connections are also within the term ‘mechanically attached connections’ as they include at least one such connection.